Let us call our trigger my_trigger. 


 
 
<pre name="code" class="java">
 
DELIMITER $$

USE `my_database`$$

CREATE
DEFINER=`root`@`localhost`
TRIGGER `my_database`.`my_trigger`
BEFORE UPDATE ON `my_database`.`main_table`
FOR EACH ROW
BEGIN
 INSERT INTO history_table 
 VALUES
 (
 OLD.field1, 
 OLD.field2,
 OLD.field3 
 );
					
END$$
 
 
</pre>




The OLD alias above refers the field value of our main_table before the edit. DEFINER is optional. Back 

quotes are also optional. 



Below is a conditional trigger. It updates our history table only when a specific field value changed, in this case, only when the value field1 has changed.


 
<pre name="code" class="java">
 
DELIMITER $$

USE `my_database`$$

CREATE
DEFINER=`root`@`localhost`
TRIGGER `my_database`.`my_trigger`
BEFORE UPDATE ON `my_database`.`main_table`
FOR EACH ROW
BEGIN
IF (OLD.field1 <> NEW.field1) THEN
 INSERT INTO history_table 
 VALUES
 (
 OLD.field1, 
 OLD.field2,
 OLD.field3 
 );
END IF;					
END$$
 
 
</pre>


<div>
<ins class="adsbygoogle"
 style="display:block; text-align:center;"
 data-ad-layout="in-article"
 data-ad-format="fluid"
 data-ad-client="ca-pub-1532779215895298"
 data-ad-slot="4831933865"></ins>
<script>
 (adsbygoogle = window.adsbygoogle || []).push({});
</script>
</div>


If you are using phpmyadmin, enter the above command like a reqular SQL command in the SQL query window. If you are 

using MySQL Workbench, select the database, right click on main_table and select alter table. A window will open 

with options near the bottom of the window. Select trigger and enter your create trigger command.




Good luck.

Create history record for every change in MySQL table - Audit trail; MySQL trigger